(1) Field of the Invention
The present invention relates to electronic musical instruments and particularly to improvements in keyboard instruments such as electronic organs. More specifically, this invention is directed to enhancing the quality of sound produced by keyboard-type electronic musical instruments and especially to the generation of signals having electrical characteristics commensurate wth the manner in which the keys are operated. Accordingly, the general objects of the present invention are to provide novel and improved apparatus and methods of such character.
(2) Description of the Prior Art
While not limited thereto in its utility, the present invention is particularly well-suited for incorporation in that type of keyboard instrument generally called an "electronic organ". An electronic organ produces audible sound in response to the depression of keys on a keyboard or keyboards. The operation, i.e., the depression, of a key by the player of a prior art electronic organs typically causes the operation of a switch. A switch, however, can only indicate whether or not the associated key has been touched. Since an electronic organ optimally is selectively employed to simulate various instruments, the simple detection of a switch closure does not provide sufficient information to enable the production of a complex command signal which may be transduced into the tone desired by the player. For example, in the playing of a piano the sound which wll be produced will be a function of how the key is depressed by the player, i.e., harder or softer. Thus, the typical prior art electronic organ could not simulate a piano with a high degree of realism.
In order to overcome the above-discussed problem it has been proposed to attempt to measure the time required for a key stroke and produce an output signal commensurate with the measured time. This approach is based upon the incorrect assumption that if the measured time is "short" there has necessarily been a "hard" touch while a "long" measured time is indicative of a "soft" key operation.
It is also to be noted that in the playing of various types of musical instruments, string instruments for example, the player will produce desired effects by means of the movements of his fingers while a note is being sounded. The well-known vibrato effect is but one example of a sound quality produced by finger movement during the production of a tone. Previously available electronic keyboard instruments have not been able to successfully simulate "secondary effects" such as vibrato.